High-grade zinc alloys

ABSTRACT

High-grade zinc alloys consisting of 0.05% to 0.25% titanium, 0.02% to 0.20% copper, 0.005% to 0.05% aluminum, the remainder high-grade zinc having a degree of purity of 99.9% to 99.995% and the use thereof as a creep resistant and ductile alloy in cold rolling applications.

United States Patent Inventor Erich ll elzel Stolberg, Germany Appl. No. 832,508

Filed June 11, 1969 Patented Oct. 26, 1971 Assignee Stolberger Zink Alrtiengesells-chaft liur Bergbau und Huttenbetrieb Aachen, Germany Priority June 12, 1968 Germany P 17 58 489.3

HIGH-GRADE ZINC ALLOYS References Cited UNITED STATES PATENTS Schroeder et al Starmann Boyle Wilson Giuliani et al.

Primary Examiner-L. Dewayne Rutledge Assistant Examiner-15. L. Weise Attorney-Michael S. Striker 75/178 AC 75/178 AC 75/178 R 75/178 R 75/178 R -grade zinc alloys consisting of 0.05% to 02% to 0.20% copper, 0.005% to 0.05% gh-grade zinc having a degree of and the use thereof as a creep re- HIGH-GRADE ZINC ALLOYS This invention relates to improved high-grade zinc alloys and more particularly to such alloys consisting of 0.05 to 0.25% titanium, 0.02 to 0.20% copper, 0.005 to 005% aluminum, the remainder consisting of high-grade zinc having a purity of 99.9%.

In German Patent application P 15 33 390.] there is described a creep-resistant zinc alloy consisting of to 1% lead, 0 to 0.05% cadmium, 0 to 1.2% copper and which additionally contains titanium in an amount of 0.05 to 0.25%, aluminum in an amount of at least 0.003 but less than 0.05%, preferably in an amount of 0.01 to 0.03% in addition to highgrade zinc and/or smelter zinc and which is free of any magnesium, lithium, beryllium and calcium.

These alloys can be identified as zinc-titanium-aluminum type alloys in which the titanium content determines the creep strength, the aluminum content the casting behavior and therewith the economy and efficiency in use. in addition to their practicality, which has been confirmed in use, the highgrade alloys of this type have also demonstrated other ad vantageous and surprising effects.

The stability of titanium containing zinc alloys is increased by providing them with copper contents offrom 0.15 to 2%. in accordance with the invention, it has now been found that with high-grade zinc having a purity of at least 99.9%, very small copper contents, i.e., below 0.2% are sufficient to increase their stability and that such alloys already possess in the cold-rolled state. a considerable creep resistance and ductility, this without any heat treatment. Heat treatment if it is to be applied can be carried out at lower temperatures than heretofore possible.

The invention therefore lies in the finding that high-grade zinc alloys consisting of 0.05 to 0.25% titanium, 0.02 to 0.20% copper, 0.005 to 0.05% aluminum, the remainder of highgrade zinc having a degree of purity of 99.9 to 99.995% are highly suitable as creep resistant and ductile alloys when cold rolled.

The following examples are given for the purpose of illustrating the invention and are not to be construed as a limitation thereof.

In the examples using a horizontally disposed ingot mold, there was cast in each case a 1,000 kg. block having a thickness of 80 mm. This block was rolled at 250 C. down to an 8 mm. thickness and thereafter at room temperature cold rolled down from 8 mm. to 0.8 mm.

EXAMPLE 1 [A110 to 0.89; copper, 0.1 to 0.15% titanium. Aluminum maximum 0.001%, remainder high grade zino.]

l Kg./mm.'-' for 1",, expansion per year.

EXAMPLE 2 [All0y0- .2 to 0.57 copper, 0.1 to 0.15% titanium. Aluminum maximum 0.001% remainder high grade zinc.]

Stability, Folding,

kgJm. 180 C. Creep resist State I once I Rolled 20 26. Broke... Good. 2.5 After 2 hours, 200 0.. 18 23 Good .410- 7. 2

l Kgjmm. for 1% expansion per year.

EXAMPLE 3 [A1loy=0.05 to 1.15% copper, 0.10 to 0.16% titoninm, 0.01 to 0.02% nluininurn. Remainder high grade zinc.)

Stability, Folding, kg./m. 180 0. 1 Resist- Stute I once 1 Rolled 10 20 Good. Good. 5 After 2 hours, C 17 22 do o.

1 To creep lire/min. for 1% expansion per year. *Verllicnl and/or parallel in the direction ol rolling.

The titanium-aluminum sheet alloy having high copper contents of less than 0.2% and preferably of less than 0.05 to 0.1% had a considerable resistance to creep on working without evidence of any breakage in the rolled state. This is a decisive advance in the art, as the heretofore produced alloys with higher copper contents and no aluminum lose most of their creep strength following permanent annealing, when the thusly treated sheet material was cold cast during processing, as for example by pressing.

The possible heat treatment of the alloy in accordance with the invention can be carried out advantageously in the tem perature range of from 120 to C. 1n the same temperature range, the alloy can also be warrnrolled. 

2. High-grade zinc alloy according to claim 1 containing 0.05 to 0.15% copper.
 3. High-grade zinc alloy according to claim 1 containing 0.05 to 0.10% copper.
 4. High-grade zinc alloy according to claim 1 consisting of 0.05 to 0.15% copper, 0.10 to 0.15% titanium, 0.01 to 0.02% aluminum, the remainder high-grade zinc having a degree of purity of 99.9 to 99.995%. 